[Effects of ceftizoxime suppository rectal dosing on cecal microflora in mice]

The effect of ceftizoxime suppository (CZX-S), a new rectal preparation of ceftizoxime (CZX), against cecal microflora of mice following consecutive rectal administration was compared with that after subcutaneous administration of CZX. The numbers of aerobic and anaerobic bacteria except Enterobacteriaceae of cecal microflora were not markedly changed by the rectal administration of CZX-S at a dose of 25 mg/kg 3 times daily for 10 days. Although the number of Enterobacteriaceae was decreased, recovery was rapidly observed after completion of the administration period. In the case of subcutaneous administration, a decrease in Enterobacteriaceae was also observed, but this was no more remarkable than that occurring with rectal administration. Moreover, effects on the state of feces, i.e., diarrhea, were not observed in any of the mice. The peak level of CZX in the cecum contents when administered rectally at a dose of 25 mg/kg was 13.8 micrograms/g at 4 hours, while it was less than the determination limit (2.0 micrograms/g) when administered subcutaneously at the same dose.